The present invention relates to an auxiliary member for use in connection with grinding machinery and more particularly for grinding the internal bore, i.e. the lumen of hollow workpieces which are also of external circular cross-section.
As is well known, in grinding the internal circular surface of such a workpiece--which, in most cases, is intended to serve as a machine-part--it is of utmost importance that not only maximal precision is observed, but also that the internal longitudinal axis, i.e. that of the bore or lumen and that of the external circle coincide. It has been customary therefore to resort to different, but in all cases rather complicated clamping and centering means when attempting to grind the internal surface of such a workpiece on which the outer grinding had already been done. Obviously, for each of the operations, the external grinding and the internal grinding, the workpiece had to be centered and clamped separately, hence the difficulty in obtaining the required precision of work and required concentricity.
Furthermore, it is common for all the different systems to clamp the workpiece to the revolving cam of the grinding machine, the outside diameter of which workpiece has already been ground, this being done to secure the necessary concentricity and precision run-out between the inside and outside diameters.